*{
	margin: 0;
	padding: 0;
}

/*
 * border-top: 1px solid black;不可用
 */
/*.wrapper{
	margin-left: 100px;
	margin-top: 100px;
	width: 100px;
	height: 100px;
	background-color: black;
	overflow: hidden;
	
}
.content{
	margin-left: 50px;
	margin-top: 50px;
	width: 50px;
	height: 50px;
	background-color: green;
}*/
/*==============================line2=========*/
.box1{
	background-color: red;
	margin-right: 100px;
}
.box2{
	margin-left: 100px;
	background-color: green;
}
.demo1{
	background-color: red;
	margin-bottom: 200px;
}
.demo2{
	background-color: green;
	margin-top: 100px;
}
